This is the law that notoriously specifies “for every action, there is an opposite and equivalent reaction.” When 2 marbles collided and rebounded in your childhood video games, its a concept you may recall from the days. When it comes to the tiny world, things arent so uncomplicated.
Credit: Public domain CC0 picture.
Image a puny sperm cell, with its whip-like tail, wriggling its way through thick fluids to reach the treasured egg. Out of countless sperm, only one gets to chance to fertilize the egg. However, its amazing any make it past the finish line offered Newtons 3rd law of movement.
Swimming versus the present
The way the sperm and green algae handle to beat Newtons third law of movement is owed to the odd flexibility with which these flagella move. Their flagella interact with their environments in a non-reciprocal way, bending in simply the right way in action to the fluid. This indicates they do not constantly receive a equal and opposite response.
Image an undersized sperm cell, with its whip-like tail, wriggling its method through thick fluids to reach the prized egg. The way the sperm and green algae manage to beat Newtons third law of movement is owed to the odd elasticity with which these flagella move. Their flagella engage with their surroundings in a non-reciprocal way, flexing in just the ideal way in action to the fluid.
This property allows the cells to move easily even through the thickest fluid without losing much energy. And because lots of microbes have flagella, there likely are many other small rule-breakers waiting to be discovered.
Beyond the excitement of finding out more about nature, understanding these motions can improve the style of tiny robots or harness these principles to comprehend collective habits in larger systems.
Kenta Ishimoto, from Kyoto University, and his team delved deep into this puzzling behavior. They closely observed human sperm and the movement of green algae, Chlamydomonas, both of which swim utilizing slender, flexible flagella (the tail).
Heres the conundrum: the thick liquid environment around these cells ought to sap away all their energy, keeping them still. Imagine trying to swim in a pool of honey; thats what these cells deal with in highly viscous fluids.
The findings appeared in the journal PRX Life.
